Circuit interrupters



Feb. 14, 1956 N. A. SPEARS, JR

CIRCUIT INTERRUPTERS 5 Sheets-Sheet 1 Filed Sept. 28, 1951 INVENTOR Neilus A. Speors,dr. Q/

ATTORNEY IIII. III/I.

Fig.22. Fig.23.

TIC

WITNESSES.

Feb. 14, 1956 N. A. SPEARS, JR

CIRCUIT INTERRUPTERS 5 Sheets-Sheet 2 Filed Sept. 28, 1951 Fig.9.

Fig.lO. 42 42 INVENTOR Neilus A. Spears, Jr. 6 1/ ATTORNEY Feb. 14, 1956 N. A. SPEARS, JR 2,734,970

CIRCUIT INTERRUPTERS Filed Sept. 28, 1951 5 Sheets-Sheet s m Fig.|2.

T Ill l2 IGQ ISS Insulation I45 WITNESSES: INVENTOR I53 Neilus A. Spears, Jr. 22/, 4. 6W1- Qz i sJ ATTORNEY Feb. 14, 1956 N. A. SPEARS, JR 2,734,970

CIRCUIT INTERRUPTERS Filed Sept. 28, 1951 5 Sheets-Sheet 5 Fig. 24.

WITNESSES: INVENTOR Neilus A. Speors,dr.

S e atent 2,734,970 CIRCUIT INTERRUPTERS Neilus A. Spears, Jr., Pittsburgh, Pa., assignor to Westingllouse Eieetric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Application September 28, 1951, Serial No. 248,764 29 Claims. ((31. Zen-447) This invention relates to circuit interrupters, in general, and, more particularly, to arc-extinguishing structures therefor.

A general object of my invention is to provide an improved, more effective and compact arc-extinguishing device, particularly of the air-break type, than has been used heretofore.

Another object is to provide an improved circuit inter rupter utilizing a stack of magnetic plates to bias the arc laterally and also to provide a plurality of dielectric splitters to cool the ionized arc gases.

Another object of my invention is to provide an improved circuit interrupter using a pair of opposed stacks of magnetic plates with a plurality of dielectric splitters, joining the ends of these stacks, to assist in cooling and deionizing the arc gases.

A further object is to provide an improved arc-extinguishing structure of the type set forth in either of the two immediately preceding paragraphs, in which an exhaust chimney is provided to the rear of each stack of magnetic plates to facilitate the exhausting of the arc gases through the magnetic plate structure.

Another object is to provide an improved circuit interrupter using a stack of spaced V-shaped magnetic plates in conjunction with a plurality of dielectric splitters to rapidly bring about are extinction.

Another object is to provide an improved arc-extinguishing device of the type heretofore described in which a battle is used at the lower end of the chimney to facilitate the upward movement of the arc gases through the chimney. I

, Although certain features of my invention are par ticularly and usually applicable to circuit interrupters of high power using direct-current voltages of, say, 750 to 1000 volts D. C., these same features are applicable to alternating current circuit interrupters, and to directcurrent interrupters of higher or lower voltage ratings. One feature of my invention particularly desirable is the fact that although a blowout coil may be used, it is not necessary, and, in fact, a particular form of the inter rupting structures, hereinafter to be described, interrupted 50,000 amperes at 1000 volts D. C. without the use of a blowout coil.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

Figure 1 is a substantially vertical sectional view through an air-break type of circuit interrupter embodying my invention, the contact structure being shown in the closed circuit position;

Figure 2 is a plan View in section taken along the line II-II of Figure 1, looking in the direction of the arrows;

Figure 3 is a fragmentary view in section taken along the lines IIIIII of Figure 1, looking in the direction ofthe arrows; v 3

Figure 4 is a vertical sectional view taken along the line IV-IV of Figure 1, looking in the direction of the arrows;

Figure 5 is an end elevational view of the interrupter of Figure 1 taken along the line V-V of Figure 1;

Figure 6 is a vertical sectional view taken along the line VI-VI of Figure 1, looking in the direction of the arrows;

Figures 7-l1 are side elevational views of plate details used in the interrupting structure of Figure 1;

Figure 12 is a substantially vertical sectional view through a modified type of air-break circuit interrupter, embodying the principles of my invention, the contact structure being shown in the closed circuit position;

Figure 13 is a view in section taken along the line XIII-XIII of Figure 12, looking in the direction of the arrows;

Figure 14 is a fragmentary view in section taken along the line XIVXIV of Figure 12, looking in the direction of the arrows;

Figure 15 is a vertical sectional view taken along the line XV-XV of Figure 12, looking in the direction of the arrows;

Figure 16 is a plan view of one of the magnetic plates used in the interrupter of Figure 12;

Figure 17 is a top plan view of one of the spacer elements utilized in the modification of Figure 12;

Figure 18 is a side elevational view of one of the spacer strips separating the magnetic plate structure in my improved circuit interrupter;

Figure 18A is an end view of the spacer strip of Fig. 18;

Figure 19 is a side elevational view of a plate item used in the interrupter of Figure 12;

Figure 20 is a side elevational view of one of the ceramic arc shields used in the interrupter of Figure 1;

Figure 21 is an end elevational view of the shield of Figure 20;

Figures 22 and 23 are side and end elevational views of spacer strips used in my invention; and I Figure 24 is a substantially vertical sectional view through a modified type of circuit interrupter, embodying the principles of my invention and similar to the circuit interrupter of Figures 12-19 with the exception that only a single stack of magnetic plates is utilized, thereby adapting the invention to the situation involving a circuit interrupter of short length.

Referring to the drawings, and more particularly to Figure 1 thereof, the reference numeral 1 generally designates a circuit interupte'r, particularly one of the airbreak type, having contact structure 2 and an adjacently disposed a'rc chute 3 into which the established arc is directed and extinguished. The contact structure 2 includes a stationary contact 5 having a main contact portion 6, and an arcing portion or tip 7. The stationany contact 5 has an integral extension 8, which extends rearwardly of the interrupter 1 and to which a line con nection may be made.

Cooperating with the stationary contact 5, and moving with respect thereto, is a movable contact generally designated by the reference numeral 9 and including a movable main contact 16, a movable arcing contact 11, and a movable are born extension 12. The movable contact 9, is of course, situated at the extremity of a movable contact arm, not shown, which may be pivotally mounted and actuated by any suitable mechanism, which forms no part of my invention.

The contact structure 2 is disposed with respect to the arc chute 3 so that any are established between the stationary and movable arcing contacts 7, 11 will be moved upwardly and into the arc chute 3 by the thermal draft up through the center of the arc chute 3 together with the tendency of any are to bow outwardly as indicated by the 'dotted line 13 (Fig. 1).

the, insulating plates 62, 77, and 83 are not only spaced apart by the sleeves encircling the spacing rods 74, but also are spaced the proper distance apart by the spacing strips 82 provided in the beveled edges 81 and slots of top holding strip 65 and holding strip 27, respectively.

As observed in Figure 7 of the drawings, the asbestos plate 83 has apertures 76 provided therein to accommodate the spacing rods 74, and lug portions 79 to fit between the spacing strips 27, 65. Also, each asbestos plate 83 has a V-shaped slot 84 provided at the lower end thereof, which is of the same configuration as the V-shaped slot 45 of the iron plates 41, the purpose for which will be more fully apparent hereinafter.

On the other side of the asbestos plate 83 from the plates 77 is a plurality of suitably spaced composite plates 85 (Figure 4). Each composite plate 85 includes a top insulating dielectric splitter plate 86 and an abutting magnetic plate 41 disposed in the same plane. As observed in Figure 1, the magnetic plate 41 is of the same thickness as the asbestos plate 86 so that the asbestos plate 86 merely forms an insulating extension of the magnetic plate 41.

It will be observed that the composite plates 85 are spaced rather closely together. This is accomplished by a plurality of short insulating sleeves 88 encircling the spacing rods 7'4, and by using a plurality of thin insulating spacer strips 82a of the same configuration as the spacer strip 82 of Figure 22 but thinner.

Consequently, the assembly operation for the top of the arc chute 3 is somewhat similar to that employed in the stack 44, namely, employing insulating spacer strips 82, 82a within the groove 80 of the holding strip 27, and alternating pairs of strips 82, 82:: with the plates 85. As mentioned, the sleeves 88, 75 assist in spacing the plates the proper distance apart. Finally the strips 65 are inserted from the end of the arc chute 3 and secured in place by the screws 66.

To the left of the end composite plates 85 is disposed a pair of relatively long spacing sleeves 89 encircling the spacing rods 74 and a pair of thick spacing strips 821) of the same configuration as the spacing strips 82 of Figure 22 but thicker. Then follows an insulating asbestos plate 90, which is the same form as plate 90a shown in Figure 11, with the exception that the recesses 91, hereinafter referred to, are .not employed. Then follows immediately adjacent to the plate 99 a plate 90a of the same configuration as the plate 90 but employing the circular recesses 91. A pair of thin circular plates 92 is placed within the re cesses 91 and is engaged by the ends 94 of a pair of clamp screws 95, which passes through apertures 96 provided in the end wall 15 of the housing 14 (Figure 1) and threadedly engages threaded apertures 97 provided in an insulating clamp plate 98. The clamp plate 98 (Figure 5 has two threaded apertures 99 (Figure 1) provided adjacent the lower end thereof. Mounting screws 100 (Figure 5) pass through the end wall 15 of the housing 14 and engage the threaded apertures 99 to fixedly clamp the plate 98 to the end Wall 15 of the housing 14.

It will be apparent that upon rotation of the clamp screws 95, the ends 94 thereof will engage the plates 92 and press the plate 90a toward the right, as viewed in Figure 1, to compress the dielectric splitter stack 72.

The operation of the circuit-interrupting device as set out in Figures 1l0 will now be explained. During the opening operation, the movable contact 9 moves toward the left away from the stationary contact 5, drawing an are 13 therebetween. The are 13 transfers to the arc horn extension 12 of the movable contact 9 and rapidly moves to the position 101 Within an open flash space 18. The are 191 (Figure 3) is attracted to the magnetic stack 44 of plates 41 at one side of the open flash space 18 and is drawn within the groove 46 and onto the plates 41 to become subdivided thereby. The hot arc gases pass between the plates 41 and into the chimney or exhaust passage 102, provided to the left of the stack 44 of magnetic plates.

The plates 90, 90a provide a continuation of the chimney 102 at the upper end of the arc chute 3.

It will be observed that the closure plate 17 closes the lower end of the chimney 102 so that the exhaust arc gases pass upwardly, as indicated by the arrows 103, past the plate 90a and out of the arc chute 3. Also, the top portion of the are 101 within the open flash space 18 is attracted by the plurality of magnetic plates 41 provided in the stack structure 72 of composite plates 85. The upper portion of the are 101 (Figure 4) is moved into the groove 10.4. provided by the alignment of the slots 45 of the vertically disposed magnetic plates 41.

The are 101 moves through the vertically disposed magnetic plates 41 and is subdivided thereby, the exhaust arc gases passing upwardly in the direction indicated by the arrows 105, and becoming cooled by the surfaces of the plates 86, 83, and 77.

The combination of the magnetic stack 44 at one side of the flash space 18 in conjunction with the chimney 102 and the horizontal stack of magnetic and insulating plates 85 at the upper side of the flash space 18 provides a compact and effective arrangement for insuring rapid are extinction in a minimum of space. The provision of the insulating extensions 86 insures rapid cooling of the arc gases, and prevents flashover occurring at the top of the arc chute 3.

Figures 12l9 illustrate a modification of my invention particularly adaptable for high power circuit interrupter ratings. It will be observed that generally I provide two vertically disposed stacks 10.9 of magnetic plates at two sides of the flash space 18. As was the situation in connection with Figure 1, the magnetic plates are preferably spaced vertically apart and have the same mounting construction as heretofore described in connection with the interrupter of Figure 1. Along the top of the modified type of arc chute of Figure 12 is a stack 111 of dielectric splitter plates each having a configuration as shown more clearly in Figure 15, and the several insulating plates being spaced apart. As mentioned, the interrupter of Figure 12 is particularly adaptable for high voltage and high power ratings and, therefore, the vertically disposed magnetic plates 41, as used in Figure 1, are eliminated, and there merely exists a plurality of vertically disposed insulating plates 112, preferably of an arc-resisting material such as asbestos.

Dealing specifically with the structure of the modified type of arc chute 110, and referring particularly to Figures 12 and 13, it will be observed that again I have provided a rectangularly shaped insulating housing, designated gen erally by the reference character 113. The rectangular housing 113 has two sides 114 and two ends 115.. The top and bottom of the housing 113 are open, with the exception of certain closure plates 116 hereinafter described. An insulating mounting panel 117 is provided, against which is disposed a U-shaped channel member 118. One or more mounting bolts 119 are provided to fixedly secure the mounting channel 118 against the panel 117. Other mounting bolts 120 pass through the channel member 118, through the panel 117, and also through a metallic mounting plate 121, fixedly disposed on the opposite side of the panel 117. The latter is, in turn, secured by one or more bolts 122 to support structure 123, the latter being of conventional type and forming no part of my invention.

A plurality of mounting bolts 124 passes horizontally through the legs 125 of the channel member 118 and also through the right-hand end of the housing 113 as viewed in Figure 12. Spacer sleeves 126 encircle the mounting bolts 124 being disposed between the inner sides of the legs 125 of channel member 118 and the outer walls 114 of the housing 113. Nuts 127 are drawn up on the bolts 124 to provide a resulting rigid construction.

The construction of the two vertically disposed stacks 109 of magnetic plates will now be described. Two pairs 7 of insulatingmounting strips 128 (Figure 14) are secured by screws 129 to each side 114 of the housing 113. Each mounting strip has a groove 130 provided therein, the two grooves 130 of each cooperating pair of mounting strips 128 serving to retain insulating spacer strips 39, more particularly shown in Figure 18. The insulating strips 39 serve to space magnetic plates 131 apart, the latter being more clearly shown in Figure 16 of the drawings. As noted in Figure 16, each iron plate 131 has a pair of lug portions 132 which are of the right width to fit between cooperating mounting strips 128, as more clearly shown in Figure 14 of the drawings. Also, each iron plate 131 has a V-shaped notch 133 provided therein, which, upon alignment with the other plates 131, forms a V- shaped groove generally designated by the reference numeral 134.

The method of assembly of the interrupter of Figure 12 is the same as in the interrupter of Figure 1, namely, first putting an iron plate 131 in position between the two pairs of vertically disposed mounting strips 128, as shown in Figure 14, then inserting two spacer strips 39 in position within the two sets of cooperating grooves 130, then placing another iron plate 131 in position, and so on until a plurality of horizontally disposed spaced magnetic plates 131 is provided, resulting in the stacks 109 of magnetic plates.

At the lower end of each stack 109 of magnetic plates 131 is a pair of insulating block members 135, the configuration of which is more clearly shown in Figure 17. Each block member has a pair of laterally disposed threaded apertures 136, which retain mounting screws 137, the latter passing outwardly through the side walls 114 of the housing 113. Also, each block 135 has a pair of vertically disposed threaded apertures 138 which serve to retain screws 139 (Figure 12), the latter serving to retain the closure plates 116 in position.

As was the case with the closure plate 17 of Figure 1, the closure plates 116 of Figure 12 close off the lower ends of a pair of chimneys 140 provided immediately in back of the stacks 109 of magnetic plates 131.

Each block 135 of the left hand pair, as viewed in Figure 12, is notched, as at 141, to accommodate an arc horn 143, the latter being secured by a mounting screw 144 to the outer end wall 115 of the housing 113. The lower end of the arc horn 143 is connected by a flexible strap 1 15 to a movable contact arm 147, the latter being pivotally mounted upon a fixed axis, as is customary in the art. At the free end of the pivotally mounted movable contact arm 147 is a movable main contact 148 and a movable arcing contact 149. The movable main contact 148 cooperates with a stationary main contact 150 forming a part of a stationary contact 151, the latter being secured to the inner extremity of a terminal stud 153, the latter passing through an insulating bushing 154.

Also associated with the stationary contact 151 is a stationary arcing contact 155, which cooperates with the movable arcing contact 149 to draw an arc therebetween within the open flash space 18. A second arc horn 156 is secured by screws 157 to the stationary contact 151 in a manner more clearly shown in Figures 12 and 13.

A pair of insulating arc resistant plates 158 is secured to the inner walls 114 of the housing 113 by a plurality of mounting screws 159, the latter also passing through a pair of arc guide shields 160, which are generally similar to the arc guide shields 19 of Figures 20 and 21. The arc guide shield 160 has a plurality of apertures 161 formed therein to accommodate the screws 159, and after the nuts 162 are secured into place, cement is used to cover the nuts 162 to provide a smooth interior surface for the arc guide shields 160. Each shield 16% has a groove 163 formed therealong into which is placed a flame plate 164, the latter being secured by screws 165 (Figure 12) to the side walls 114 of the housing 113.

The construction of the stack 111 of dielectric splitter plates at the top of the arc chute 110 bounding the upper side of the flash space 18 will now be described. Here again two pairs of insulating mounting strips 166 are employed, as more clearly shown in Figure 15 of the drawings. Each mounting strip is provided with a groove 167 which serves to retain a plurality of spacer strips 39, as more clearly shown in Figure 18. The spacer strips 39 space a plurality of arc-resisting insulating plates 112 apart, as more clearly shown in Figure 13. Referring to Figure 15, it will be noted that each asbestos plate 112 has a curved slot 168 provided therein, and the plates 112 are alternated during assembly so that a zigzag arcing slot 169 is provided. Thus, as the arc is moved upwardly within the arcing slot 169, it is forced to assume a zigzag shape and is cooled by the restricting portions 170 of the slots 168.

At the outer ends of the stack 111 is placed a pair of wider spacer strips 171 within the slots 167 and then follows a pair of insulating extension plates 172, the latter having a configuration more clearly shown in Figure 19 of the drawings. The insulating extension plate 172 is so called, inasmuch as it forms an extension of the chimneys 140, the latter, as mentioned, being disposed immediately behind the stacks 109 of magnetic plates 131. Thus, the

chimneys 149 are extended past the stack 111 of splitter plates 112 by the presence of the extension plates 172 which are secured between the mounting strips 166 by the lug portions 173 thereon formed. Preferably, the extension plates are made of an.arc-resistant material, such as sheet asbestos.

To maintain the stack 111 in compressed state, two pairs of spacer stops 174 are utilized, being fixedly secured by mounting screws 175 to the side walls 114 of the housing 113, as more clearly shown in Figure 13.

The operation of this embodiment of my invention will now be described. During the opening operation, the movable contact arm 147 rotates about its fixed axis, not shown, to separate the movable main contact 148 away from the stationary main contact 156, and subsequently to separate the movable and stationary arcing contacts 149, 155. This is provided by the construction and re siliency of the stationary contact 151, which is of conventional design and forms no part of my invention.

The are 176 initially drawn between the contacts 149, 155 is moved upwardly into the open flash space 18 by the thermal draft through the arc chute 110, and also by the inherent looping action of the arc. The looping action is, of course, caused by the flow of current through the interrupter in a U-shaped path provided by the terminal stud 153 and by the lower terminal stud, not shown, electrically connected to the movable contact arm 147. As is well known, current in a looped circuit tends to expand the loop by the magnetic forces which come into play, and, therefore, the initially drawn are 176 will bow or loop upwardly into the flash space 18 and will soon have its terminals transferred to the stationary arc horns 143, 156.

The position of the arc at this point of the opening operation is represented by the dotted line 177. The stacks 109 of magnetic plates 131 will attract the are 177 and will cause the latter to move thereinto, as indicated by the dotted line 178, which indicates a later position of arc travel. The are 178 will be magnetically drawn into the grooves 134 and onto the magnetic plates 131, where it will become subdivided into a plurality of serially related arc portions 179, the arc gases passing laterally through the stacks 199 and into the chimneys 14%.

The arc gases will then be exhausted upwardly through the chimneys 140 and past the extension plates 172 to the region externally of the arc chute 11%. The upper horizontal portion of the arc 179 will pass into the arcing slot 169 of the stack 111 of dielectric splitter plates 112, and will be moved in a zigzag manner upwardly into the restricted portions 170 of the slots 16%. Intensive cooling and deionization follow within the stack 111. Also, in-

- practice.

tensive cooling occurs within the stacks-109 of "magnetic plates 131. The net result is a very rapid and eflicient extinction of the arc. The fully open circuit position of the movable contact 180 is indicated by the dotted lines in Figure 12.

The modification of my invention illustrated in Figure 24 is substantially identical with that illustrated in Figures 12-19 with the exception that the stack 109 of magnetic plates 131 nearest to the panel 117'is eliminated. This may be necessitated by the fact that space restrictions require the stationary contact 182 to be closely positioned to the mounting panel 183. Thus, there would be no room for a second stack 109 immediately adjacent to the panel 183, and consequently it must be eliminated. However, even in such a situation certain advantages result from an application of my invention. The other parts of the modified type of are chute 184 of Figure 24 are identical in construction to that illustrated heretofore specifically in Figures 12-19; consequently, it is not believed necessary to repeat the above description. The method of operation is the same as that heretofore explained with the exception that the arc 185 extending upwardly from the arc horn 156 is not engaged by a panel end stack 169 of magnetic plates. Reliance must be had upon the single stack 109 of magnetic plates 131 and also upon the stack 111 of dielectric splitter plates disposed along the top of the arc chute 184 above the flash space 18 to bring about are extinction.

Although in the foregoing structures I have referred to vertical and horizontal stacks of plates, it is to be clearly understood that the circuit interrupters, as a whole, may be oriented in any direction. Exceptional results are, however, obtained when the circuit interrupters are mounted as shown, for then advantage can be taken of the natural thermal draft upwardly through the arc chutes.

It will be observed that a novel feature of the arc chutes is that more and more iron plates 41, 131 are inserted into the path of the arc. Thus, as the arc moves up into the arc chute, more and more energy is extracted from the are by the iron plates heating up. Also, the arc voltage is progressively raised by the insertion of an increasing number of magnetic plates as the arc moves up. Finally, when the arc current has been reduced to a low value, the back of the arc is broken, so to speak, by the insertion of the dielectric splitter plates of the horizontal stacks 72, 111 when the arc is in a weakened condition. The chimneys 102, 140 behind each stackof iron plates ex haust gases, which accumulate as the arc encounters the iron plates. Gas pressure in the central region of the arc chutes has the effect of helping to move the are through the iron stacks so that are energy is etfectively removed. The circuit interrupter of the type set-out in Figure 1 has successfully interrupted 50,000 amperes at 100 volts D. C. without a blowout coil.

The novel arrangement of iron and dielectric plates in the foregoing types of arc chutes removes the difficulty heretofore experienced in applying iron plate chutes to the higher voltages. The presence of a large amount of dielectric material insures that the circuit will remain open in spite of any streamers of iron which may have shorted out some of the plates. The arrangement of iron and dielectric plates in the arc chutes results in greater space economy in the arc-chute from that of previous It will be noted that at the moment of arc interruption the archas traversed practically the whole volume of the arc chute.

Although I have shown and described specific structures, it is to be clearly understood that the same were merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. A circuit interrupter including a relatively'stationary contact cooperable with a movable contact to establish an arc, 'an arc chute for extinguishing the are "including a plurality of spaced conducting plates disposed along one side of the arcing space in the general plane of contact movement, said conducting plates being positioned substantially transversely to the established arc and insulated from one another so that said are may move thereinto in the form of a plurality of serially related arc portions, and a plurality of spaced insulating plates disposed along another side of the arcing space in the general plane of contact movement and also disposed substantially transversely of the established arc.

2. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a pair of stacks of spaced magnetic plates disposed along two sides of the flash space, the established are being drawn'toward the stacks to effect the extinction thereof, and a stack of dielectric splitter plates disposed along a third side of the flash space.

3. A circuit interrupter including contact means for establishing a single are, an arc chute for extinguishing the single arc including an open flash space, said are chute including a pair of stacks of spaced magnetic plates disposed along two sides of the flash space for receiving said single arc, the established single are being drawn toward the stacks to effect the extinction thereof, and an exhaust chimney disposed in back of at least one stack to facilitate the venting of the exhaust arc gases.

4. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the arc including an open flash space, a pair of stacks of spaced magnetic plates disposed along two sides of the flash space, the established are being drawn toward the stacks to effect the extinction thereof, a stack of dielectric splitter plates disposed along a third side of the flash space, and an exhaust chimney disposed in back of at least one stack to facilitate the venting of the exhaust arc gases.

5. A circuit interrupter including contact means for establishing an are, an arc chute for extinguishing the are including an open flash space, a stack of spaced magnetic plates disposed along one side of the flash space, a plurality of spaced dielectric plates disposed along another side of the flash space, and a plurality of spaced magnetic plates co-extensive with the dielectric plates and disposed to the inner side thereof within the arc chute.

6. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a stack composed only of spaced magnetic plates disposed along one side of the flash space and having venting passages therebetween, a plurality of spaced dielectric plates disposed along another side of the flash space, and each magnetic plate having a V-shaped slot provided therein to facilitate the entry of the arc thereon.

7. A circuit interrupter including contact means for establishing a single arc, an arc chute for extinguishing the single arc including an open flash space, a pair of stacks of spaced magnetic plates for receiving said single are disposed along two sides of the flash space in the general plane of contact movement, the established single are being drawn toward the stacks to effect the extinction thereof, and each magnetic plate having a V-shaped slot provided therein to facilitate the entry of the arc thereon.

8. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a pair of stacks of spaced magnetic plates disposed along two sides of the flash space, the established are being drawn toward the stacks to effect the extinction thereof, a stack of dielec tric splitter plates disposed along a third side of the flash space, and each magnetic plate having a V-shaped slot provided therein to facilitate the entry of the arc thereon.

9. A circuit interrupter including contact means for establishing a single arc, an arc chute for extinguishing the single are including an open flash space, a pair of stacks of spaced magnetic plates disposed along two sides of the flash space for receiving said single arc, the established single arc being drawn toward the stacks to effect the extinction thereof, an exhaust chimney disposed in back of at least one stack to facilitate the venting of the exhaust arc gases, and each magnetic plate having a V- shaped slot provided therein to facilitate the entry of the arc thereon.

10. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a pair of stacxs of spaced magnetic plates disposed along tWo sides of the flash space, the established are being drawn toward the stacks to effect the extinction thereof, a stack of dielectric splitter plates disposed along a third side of the flash space, an exhaust chimney disposed in back of at least one stack to facilitate the venting of the exhaust arc gases, and each magnetic plate having a V-shaped slot provided therein to facilitate the entry of the arc thereon.

11. A circuit interrupter including contact means for establishing an are, an arc chute for extinguishing the are including an open flash space, a stack of spaced magnetic plates disposed along one side of the flash space, a plurality of spaced dielectric plates disposed along another side of the flash space, a plurality of spaced magnetic plates coextensive With the dielectric plates and disposed to the inner side thereof within the arc chute, and each magnetic plate having a V-shaped slot provided therein to facilitate the entry of the arc thereon.

12. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a pair of stacks of spaced magnetic plates disposed along two sides of the flash space, the established are being drawn toward the stacks to effect the extinction thereof, a stack of dielectric splitter plates disposed along a third side of the flash space, and each dielectric splitter plate having a convergent slot provided therein with the Wider portion thereof facing the flash space.

13. A circuit interrupter including contact means for establishing an are, an arc chute for extinguishing the arc including an open flash space, a pair of stacks of spaced magnetic plates disposed along two sides of the flash space, the established are being drawn toward the stacks to effect the extinction thereof, a stack of dielectric splitter plates disposed along a third side of the flash space, an exhaust chimney disposed in back of at least one stack to facilitate the venting of the exhaust arc gases, and each dielectric splitter plate having a convergent slot provided therein with the Wider portion thereof facing the flash space.

14. A circuit interrupter including contact means for establishing an are, an arc chute for extinguishing the are including an open flash space, a stack of spaced mag netic plates disposed along one side of the flash space, a plurality of spaced dielectric plates disposed along another side of the flash space, a plurality of spaced magnetic plates coextensive with the dielectric plates and disposed to the inner side thereof Within the arc chute, and at least some of the magnetic plates having V-shaped slots provided therein facing the flash space.

15. A circuit interrupter including a relatively stationary contact cooperable with a movable contact to establish an are, an arc chute for extinguishing the arc including a plurality of spaced conducting plates disposed along one side of the arcing space in the general plane of contact movement, said conducting plates being positioned substantially transversely to the established arc and insulated from one another so that said are may move thereinto in the form of a plurality of serially related arc portions, said spaced conducting plates having a plurality of venting passages therebetween to vent the arc gases and assist movement of said established arc therein, a plurality of spaced insulating plates disposed along another side of the arcing space in the general plane of contact movement and also disposed substantially transversely of the established arc, and an exhaust chimney disposed in back of said plurality of spaced conducting plates to facilitate venting of the exhaust arc gases.

16. A circuit interrupter including a relatively stationary contact cooperable with a movable contact to establish an arc, an arc chute for extinguishing the arc including a plurality of spaced magnetic plates disposed along one side of the arcing space in the general plane of contact movement, said magnetic plates being positioned substantially transversely to the established arc and insulated from one another so that said arc may move thereinto in the form of a plurality of serially related arc portions, and a plurality of spaced insulating plates disposed along another'side of the arcing space in the general plane of contact movement and also disposed substantially transversely of the established arc.

l7. A circuit interrupter including a relatively stationary contact cooperable With a movable contact to establish an arc, an arc chute for extinguishing the arc including a plurality of spaced conducting plates disposed along one side of the arcing space in the general plane of contact movement, said conducting plates being positioned substantially transversely to the established arc and insulated from one another so that said are may move thereinto in the form of a plurality of serially related arc ortions, said spaced conducting plates having a plurality of venting passages therebetween to vent the arc gases and assist movement of said established arc therein, and a plurality of spaced insulating plates disposed along another side of the arcing space in the general plane of contact movement and also disposed substantially transversely of the established arc.

18. A circuit interrupter including a relatively stationary contact cooperable with a movable contact to establish an arc, an arc chute for extinguishing the are including a plurality of spaced magnetic plates disposed along one side of the arcing space in the general plane of contact movement, said magnetic plates being positioned substantially transversely to the established arc and insulated from one another so that said are may move thereinto in the form of a plurality of serially related arc portions, said spaced magnetic plates having a plurality of venting passages therebetWeen to vent the arc gases and assist movement of said established arc therein, and a plurality of spaced insulating plates disposed along another side of the arcing space in the general plane of contact movement and also disposed substantially transversely of the established arc.

19. A circuit interrupter including contact means for establishing an are, an arc chute for extinguishing the arc including an open flash space, a pair of stacks of spaced conducting plates disposed along two sides of the flash space, the established are being drawn toward the stacks to effect the extinction thereof, and a stack of dielectric splitter plates disposed along a third side of the flash space.

20. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a pair of stacks of spaced conducting plates disposed along tWo sides of the flash space, the established arc being drawn toward the stacks to effect the extinction thereof, a stack of dielectric splitter plates disposed along a third side of the flash space, and an exhaust chimney disposed in back of at least one stack to facilitate the venting of the exhaust arc gases.

21. A circuit interrupter including contact means for establishing an are, an arc chute for extinguishing the are including an open flash space, a stack of spaced conducting plates disposed along one side of the flash space, a plurality of spaced dielectric plates disposed along another side of the flash space, and a plurality of spaced 13 conducting plates coextensive with the dielectric plates and disposed to the inner side thereof within the arc chute.

22. A circuit interrupter including contact means for establishing an are, an arc chute for extinguishing the are including an open flash space, a stack composed only of spaced conducting plates disposed along one side of the flash space and having venting passages therebetween, a plurality of spaced dielectric plates disposed along another side of the flash space, and each conducting plate having a V-shaped slot provided therein to facilitate the entry of the arc thereon.

23. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a stack of spaced conducting plates disposed along one side of the flash space, a plurality of spaced dielectric plates disposed along another side of the flash space, a plurality of spaced conducting plates coextensive with the dielectric plates and disposed to the inner side thereof within the arc chute, and each conducting plate having a V-shaped slot provided therein to facilitate the entry of the arc thereon.

24. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a pair of stacks of spaced conducting plates disposed along two sides of the flash space, the established arc being drawn toward the stacks to effect the extinction thereof, a stack of dielectric splitter plates disposed along a third side of the flash space, and each dielectric splitter plate having a convergent slot provided therein with the wider portion thereof facing the flash space.

25. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a pair of stacks of spaced conducting plates disposed along two sides of the flash space, the established arc being drawn toward the stacks to eflect the extinction thereof, a stack of dielectric splitter plates disposed along a third side of the flash space, an exhaust chimney disposed in back of at least one stack to facilitate the venting of the exhaust arc gases, and each dielectric splitter plate having a convergent slot provided therein with the wider portion thereof facing the flash space.

26. A circuit interrupter including contact means for establishing an arc, an arc chute for extinguishing the are including an open flash space, a stack of spaced conducting plates disposed along one side of the flash space, a plurality of spaced dielectric plates disposed along another side of the flash space, a plurality of spaced conducting plates coextensive with the dielectric plates and disposed 14 to the inner side thereof within the are chute, and at least some of the conducting plates having V-shaped slots provided therein facing the flash space.

27. A circuit interrupter including a relatively stationary contact cooperable with a movable contact to establish an are, an arc chute for extinguishing the are including a plurality of spaced conducting plates disposed along one side of the arcing space in the general plane of contact movement, said conducting plates being positioned substantially transversely to the established arc and insulated from one another so that said are may move thereinto in the form of a plurality of serially related arc portions, and a plurality of spaced insulating plates disposed substantially at right angles to the plurality of first-mentioned plates along another side of the arcing space in the general plane of contact movement and also disposed substantially transversely of the established arc.

28. The combination in a circuit interrupter of contact means for establishing and elongating a single are, a pair of stacks of conducting plates disposed substantially at right angles to each other and disposed in the general plane of contact movement for receiving said single arc and extinguishing the same, the conducting plates in each of said stacks being insulated from each other so that the elongated arc may extend therebetween in the form of a plurality of serially related arc portions, and the series arc portions all existing at the same time.

29. The combination in a circuit interrupter of contact means for establishing and elongating a single arc, a pair of stacks of magnetic plates disposed substantially at right angles to each other and disposed in the general plane of contact movement for receiving said single arc and extinguishing the same, the magnetic plates in each of said stacks being insulated from each other so that the elongated arc may extend therebetween in the form of a plurality of serially related arc portions, and the series are portions all existing at the same time.

References Cited in the file of this patent UNITED STATES PATENTS 1,872,387 Baker et al Aug. 16, 1932 1,904,463 Hilliard Apr. 18, 1933 2,276,859 Nau Mar. 17, 1942 2,416,164 Ellis et a1 Feb. 18, 1947 2,467,937 Jackson Apr. 19, 1949 2,468,422 Wood Apr. 26, 1949 2,558,075 Dickinson et al June 26, 1951 2,596,865 Peter May 13, 1952 2,656,442 Matthias et al. Oct. 20, 1953 

